A backflow preventer is a device that protects drinking water from contamination by reverse flow from connected appliances, fittings or external sources. UK installations must comply with the Water Supply Fittings Regulations 1999 and the Water Regulations Advisory Scheme guidance, which categorises fluids and specifies the level of backflow protection required. Common devices include double check valves, reduced pressure zone valves and air gaps designed in line with BS EN 1717. Backflow protection is critical at outside taps, irrigation systems, vending machines, hose union taps and washing machines. Failure to fit appropriate devices can result in enforcement action by the local water company. Periodic testing by an accredited tester is required for higher risk devices in commercial settings.
Backflow preventer
Device protecting drinking water from contamination by reverse flow from connected appliances.
